The field of this invention is directed to fuel burners and in particular to means to control the air flow, either primary and/or secondary air to the burner.
The control of air to a burner has historically involved the rotational movement of an apertured plate relative to a fixed apertured plate in which the cross sectional opening area, being usually transverse to the flow of air, is utilized to control proper amount of stiochiometric air to the burner for optimum fuel-air ratios. In many prior art burners, this rotation has been accomplished by hand and/or a variety of complex mechanisms. Another method of automatically controlling air to a burner comprises the reciprocal movement of a disc-type valve or air adjustment plate relative to a fixed opening. Many of such prior art methods and apparatus have inherent limitations in them, are cumbersome, and in many cases are limited in size and inoperable with regard to larger size burners operating in the range of 500,000 to 2,000,000 BTU.